1. Field of the Invention
The present invention relates to an ion exchange apparatus in which, in an erect elongated tank, granular exchanger material is deposited on a nozzle plate, which is disposed above a lower liquid connection, until a level is reached that is above a horizontal drainage for the regeneration medium solution of an ascending countercurrent regeneration process, with this level being considerably below an upper liquid connection. A feed line for the regeneration medium solution leads to the tank, and disposed on a pump or valve in this feed line is an automatic switching mechanism for the alternative feeding or nonfeeding of the regeneration medium solution. The automatic switching mechanism is provided with a timing generator for dividing the regeneration phase into flow segments and rest segments.
2. Description of the Prior Art
An ion exchange apparatus of this general type where the automatic switching mechanism is not provided with a timing generator that divides the regeneration phase into flow segments and rest segments is known from German Offenlegungscchrift No. 25 55 131. In order to reduce the requirement for regeneration medium, to stabilize the flow resistance, and to improve the exchanger efficiency, with this heretofore known ion exchange apparatus a small portion of the exchanger material is confined in a pressed state between the nozzle plate and a nozzle partition disposed thereabove, with the volume ratio of confined portion to nonconfined exchanger material preferably being 1:3.5. The nozzle partition assures that the regeneration medium solution is not made use of at all in a lower safety zone of unloaded exchanger material, subsequently has a high regeneration effect on partially loaded exchanger material, and finally still has a good utilization on highly depleted exchanger material in the uppermost exchanger material zone with close-fitting dimensions. In the absence of the aforementioned pressing, unloaded exchanger material granules that are whirled upwardly during regeneration would impair the utilization of the regeneration medium solution, and downwardly whirled depleted exchanger material granules would impair the safety zone. However, as previously, a whirling or fluidization of the exchanger material disposed above the nozzle partition takes place. Increasing the concentration of the regeneration medium solution cannot be undertaken because the flow velocity during regeneration cannot drop below a certain threshold value. In the automatic switching mechanism of the ion exchange apparatus, especially the transition from the loading phase to the regeneration phase is fixed. Serving as a signal transmitter is a measuring probe that extends into the tank just above the nozzle partition. This measuring probe registers the increase of the electrical conductivity of the liquid that is being treated as the adjoining exchanger material begins to become depleted.
German Auslegeschrift No. 14 42 389 discloses an ion exchange apparatus of the aforementioned general type. This known apparatus is based on having the regeneration liquid uniformly pass through the exchanger resin without forming passages, and with the process being undertaken without excess regeneration fluid. After the regeneration has been terminated, the liquid in the resin bed is displaced by being pulsatingly subjected to a new quantity of regeneration fluid. Subsequently, the displacing fluid is withdrawn below the free resin surface, and the resin bed is flushed in a conventional manner. To produce the regeneration liquid, 2.7% hydrochloric acid, which originates from a previous regeneration process, is replenished to a concentration of 5%.
From "Ullmanns Encyklopadie der technischen Chemie", volume 8, 1957, page 830, it is known that during the regeneration of a loaded ion exchanger, in addition to the type of regeneration medium, the specific quantity and concentration thereof play a role in the process.
An object of the present invention is to provide an ion exchange apparatus that is regenerated in an ascending countercurrent, whereby the requirement for regeneration medium is reduced, the flow resistance is altered only slightly, and the exchanger efficiency is improved.